Method of making covers for pneumatic tires.



No. 651,745. Patented June I2, I900.

. T. & W. CALDWELL.

METHOD OF MAKING COVERS FDR PNEUMATIC TIRES.

(Application filed Mar. 8, 1900.)

(No Model.)

- covers when finished are Unwrap STATES lllOMAS OALDlVldLL, OF BOLTON,

ENGLAND, ASSIGNORS TO AND WILLIAM CALDWELL, or LEIGH, 'rnn RADAX PNEUMATIC TYRE COMPANY,

LIMITED, OF W'ARRINGTON, ENGLAND.

METHOD OF MAKING COVERS FOR PNEUMATlC TiRES.

SPECIFICATION forming part of Letters Patent No.

Original application filed July 18,1898,

651,745, dated June 12, 1900.

Serial No. 686,298. Divided and this application filed March 8,1900. Serial No.

7,915. (No model.)

certain newand useful Improvements in Methods of Making matic Tires, of tication.

. Our invention relates to improvements in the method of manufacturing detachable covers for pneumatic tires.

The object of our invention is to produce a newfinethod of manufacturing detachable covers for pneumatic tires, whereby the said caused to grip the concave rim of the wheel and to be held firmly and securely in position under inflation and pressure of riding without the provision of side wires or thickened edges or ribs to lock with or engage grooves or other specially-provided means upon the rim to cooperate therewith.

Our invention relates particularly to the method ordinarily practiced in producing a tire-cover such as is described and claimed in our application for Letters Patent of the United States filed July 18, 1808, Serial No.

Detachable Covers for Pneuwhich the following is'a speci- 686,298, of which the present application is a division.

In order that our invention may be better understood and carried into practice, reference is bad to the accompanying drawings, Wl16l6lI1-- I Figure l isa side view of a short section of the Woven fabric used as the basis for the tire cover before such fabric has been stretched. Fig. 2 isa crosssectional viewon the line 2 2 in Fig. 1, and Fig 3 is a crosssection of the finished tire in position.

In carrying out ourinvention We first of all employ awoven textile fabric Woven cotton cloth or canvas of sufiicient (preferably strength andfiexibility) formed somewhat shaped or U-shaped in cross-section and curved (as to its length) to approximately the radius of the tire to be made, such fabric being woven or produced, for instance, in the manner and by the means set forth in our application for Letters Patent of the United States filed July 18, 1898, Serial No. 686,298. The fabric is stretched in acirculardireetion, as hereinafter described, in such manner as to almost or entirely deprive the same of its extensibility, and this is done before the fabric is rubbered.

For stretching the fabric we preferably use a circular expanding mandrel or similar apparatus, such as is shown and described in p our application for Letters Patent, Serial No. 686,298, or any other-suitable means. The fabric is first placed upon the mandrel or other a pparatusfiv h i'ch'isa f terward expanded to the approximate practical limit of extensibilityof the fabric thereon, and while in this. stretched condition the fabric is preferably moistened with water or other liquid to render the operation of stretching more easily accomplished, the shrinkage consequent upon moistening the fabric being arrested by the mandrel. The stretching operation continues until the extensibility has been permanently removed; or it) desired, the fabric may be moistened before being poison the mandrel, in which case the stretching may be as readily accomplished; or the fabric may first be is etched on the expanding mandrel, above described, and while so stretched subjected uid, aforesaid. In all cases it is the object of this step of the method to take practically all thzstretch out of the fabric, and the sulficiency of the stretching or removal of the extensibiiity of the fabric, by whatever means, may beeasily ascertained by testing the t; ges of the fabric-While on the mandrel, the tension of the edges'becoming uitimately practically constant. I

It is desirable in stretching the fabric for a cover that the operation should be started at such a diameter as shall leave the fabric when fully stretched of the same radius as that of the making-up mandrel, so as to obviate any pnckering or slaclrncss. Having thus stretched the fabric to the approximate limit of its extensibility,

We lap the stretched fabof rubber, if'desired, may have projections on it or may be ribbed or corrugated or otherwise suitably formed-to prevent side slipping. The coating or rubbering of the fabric while ,the latter is still held in the stretched condition prevents any shrinkage of the fabric.

'When the rubber is set upon the fabric, the cover-is released and removed from the mandrel and is ready foruse. To make a cover, for example, for a twenty-eight-inch wheel, we lap the fabric, which has been woven of the shape aforesaid, on an expanding mandre twenty-six and one-half inches outside diameter and expand the same, with the fabric lapped thereon, to twenty-nine and one-half inches outside diameter. We then take off the stretched fabric from the expand ing mandrel and wind it around a collapsible mand rel twenty-seven and three-fourths inches in diameter, so as to allow one-eighth of an inch all around for the rubber coating, thereby making the outside diameter of the finished cover twenty-cight inches.

In the drawings, which illustrate the development of the tire-cover from the un stretched fabric according to our improved method, A represents the fabric composing the basis of the tire cover. (This is shown in Figs. 1 and 2.)

In Fig. 3, where the finished tire is shown, the fabric A isprovided with a coating or strip of rubber .13, 'as is usual. D represents the concave rim, and 0 represents the inner air-tube ordinarily used.

It will be found that the cover'A, by reason of its inherentcurvature and its longitudinal inextensibility, will hold itself firmly in the concavity of the rim without ribs, rods, wires, or other specially-provided means such as have heretofore usually been employed in tire-covers.

Having now described our invention, what we claim as new, and desire to secure by Let' ters Patent of the United States, is

1. Theherein-described methodof making a cover for a pneumatic tire, which consists in rendering a woven fabric, woven to the curve of the wheel, so far inextcnsiblc by stretching in a circular direction that the same when rubbered and made up will form a cover which holds itself securely on the rim under inflation.

2.' In the manufacture of detachable covers for pneumatictires,strctching a curved woven The rubber fabric, woven to the radius of the wheel or thereabout, so as to render same so far inextensible that when rubbered and made'up into covers these will hold themselves firmly on the rim under inflation without the addition of Wires or other holding-0n devices.

3. Theherein-described method of making detachable covers for pneumatic tires, which consists in rendering a woven fabric, Woven to the curve of the wheel, so far inextensible by stretching same in. a circular direction untilthclongitudinal elasticity has been per manently removed from said fabric to such an extent that the latter when rubbered and made up will form a cover which upon inflation will hold itself securely on the rim.

4. In the manufacture of detachable covers for pneumatic tires from a curved woven fabric, woven to the radius of the wheel, the process herein described of stretching such fabric so as to permanently remove the longitudinal elasticity therefrom to such an extent that such stretched fabric when made up into covers for pnen matic' tires will underinflation remain on the rim without the addition of any special fastening means.

5. The method of making adetachable cover for pneumatic tires which consists of wind ing a length of fabric-with an inherent curvature approximately the desired curvature of the finished cover and open along its interior circumferenceon an expanding mandrel and expanding, same bill said fabric is rendered practically inextensible longitudinally and making up and rubbering same, substantially as described.

(.3. The method of making a detachable cover for pneumatic tires, ing an endless band froma length of woven fabric with an inherent curvature approximately the desired curvature of the finished cover, and-open along its interior circumference; treating the baud thus formed so as to permanently remove its longitudinal extensibility, and rubbcring the same, substantially as described.

'7. The method of makingadetachable cover for pneumatic tires, which consists in forming an endless band of woven fabric with an inherent curvature approximately the desired curvature of the finished cover, and open along its interior circumference, stretching the said band on a mandrel to the limit of its extensibility, and rubbering the same, substantially as described,

In witness whereof we have hereunto set our hands in presence of two witnesses.

THOMAS CALDlVELL. XVILLIAM i (.ALDVV ELL.

\Vitncsses ERNALD MosELEY, Jon's \V. TI-IoMAs.

rhich consists in form-' 

